Rotor core, rotor, motor, manufacturing method of rotor core, and manufacturing method of rotor

ABSTRACT

A rotor core includes laminate steel plates extending in a radial direction with respect to a central axis. The laminate steel plates each include a base portion on a radially outer side of the central axis, and pieces separately disposed on a radially outer side of the base portion with penetrating portions therebetween, and arranged side by side at predetermined intervals in a circumferential direction. The laminate steel plates are laminated in an axial direction. The laminated steel plate at an upper end in the axial direction includes at least one of an outward projection extending radially outward from an outer edge portion of the base portion and an inward projection extending radially inward from an inner edge portion of the piece, and the laminated steel plate at a lower end in the axial direction includes an intervening portion between the base portion and the piece portion.

BACKGROUND OF THE INVENTION 1. Field of the Invention

The present invention relates to a rotor core, a rotor, a motor, a manufacturing method of a rotor core, and a manufacturing method of a rotor.

2. Description of the Related Art

Conventionally, a motor in which a rotor having a magnet and a shaft is disposed on a radially inner side of an annular stator having an excitation coil has been widely known.

A conventional rotor of an electric motor has an electromagnetic steel plate, magnetic pole pieces separated radially outward from a main body of the electromagnetic steel plate, and permanent magnets embedded in a radially inner side of the magnetic pole pieces.

SUMMARY OF THE INVENTION

According to an example embodiment of the present disclosure, a rotor core includes a laminate steel plate extending in a radial direction with respect to a central axis. The laminate steel plate includes a base portion positioned on a radially outer side of the central axis, and a plurality of pieces separately disposed on a radially outer side of the base portion with penetrating portions therebetween, and arranged side by side at predetermined intervals in a circumferential direction. In the rotor core, the plurality of laminate steel plates are laminated in an axial direction, the laminated steel plate disposed at an upper end in the axial direction includes at least one of an outward projection extending radially outward from an outer edge portion of the base portion and an inward projection extending radially inward from an inner edge portion of the piece, and the laminated steel plate disposed at a lower end in the axial direction includes an intervening portion that intervenes between the base portion and the piece.

According to an example embodiment of the present disclosure, a rotor includes the rotor core of the above configuration, and a plurality of magnets disposed in the penetrating portions of the rotor core. The rotor core includes a plurality of space portions which are disposed between the penetrating portions adjacent to each other in the circumferential direction, and penetrate the rotor core in the axial direction.

According to an example embodiment of the present disclosure, a motor includes the rotor of the above configuration.

A manufacturing method of a rotor core of an example embodiment of the present disclosure is a manufacturing method of a rotor core in which a plurality of laminate steel plates extending in a radial direction with respect to a central axis are laminated in an axial direction, the method including laminating divided laminate steel plates in the axial direction, each of the divided laminate steel plates including a base portion positioned on a radially outer side of the central axis, and a plurality of pieces separately disposed on a radially outer side of the base portion with penetrating portions therebetween, and arranged at predetermined intervals in a circumferential direction; laminating a connected laminate steel plate having the base portion and the pieces connected via connecting portions at an upper end in the axial direction of the divided laminate steel plates that are laminated, laminating an intervening laminate steel plate including intervening portions that intervene between the base portion and the pieces at a lower end in the axial direction of the divided laminate steel plates that are laminated, and cutting the connecting portions with a cutter by inserting the cutter into the penetrating portions.

A manufacturing method of a rotor according to an example embodiment of the present disclosure includes cutting the connecting portion with a cutter by using the rotor core produced by the above-described manufacturing method of the rotor core, and then removing the cutter from the penetrating portion and inserting a magnet into the penetrating portion.

The above and other elements, features, steps, characteristics and advantages of the present disclosure will become more apparent from the following detailed description of the example embodiments with reference to the attached drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a plan view of a motor according to a first example embodiment of the present disclosure.

FIG. 2 is a perspective view of a rotor core of the motor according to the first example embodiment of the present disclosure as viewed from above.

FIG. 3 is a perspective view of the rotor core of the motor according to the first example embodiment of the present disclosure as viewed from the below.

FIG. 4 is a plan view of a first laminate steel plate of the rotor core according to the first example embodiment of the present disclosure.

FIG. 5 is a plan view of a second laminate steel plate of the rotor core according to the first example embodiment of the present disclosure.

FIG. 6 is a perspective view of a rotor core of a motor according to a second example embodiment of the present disclosure as viewed from above.

FIG. 7 is a perspective view of the rotor core of the motor according to the second example embodiment of the present disclosure as viewed from below.

FIG. 8 is a plan view of a connected laminate steel plate of the rotor core according to the second example embodiment of the present disclosure.

FIG. 9 is a partial enlarged plan view of a connected laminate steel plate of a rotor core according to a third example embodiment of the present disclosure.

FIG. 10 is a perspective view showing an example of a cutting device used in a manufacturing method of the rotor core according to the third example embodiment of the present disclosure.

FIG. 11 is a partially enlarged plan view showing an example of a cutting tool used in the manufacturing method of the rotor core according to the third example embodiment of the present disclosure.

FIG. 12 is a partial enlarged plan view of a connected laminate steel plate showing a first example of a cutting process in the manufacturing method of the rotor core according to the third example embodiment of the present disclosure.

FIG. 13 is a plan view of a connected laminate steel plate showing a second example of the cutting process in the manufacturing method of the rotor core according to the third example embodiment of the present disclosure.

FIG. 14 is a plan view of a connected laminate steel plate showing a third example of the cutting process in the manufacturing method of the rotor core according to the third example embodiment of the present disclosure.

FIG. 15 is a perspective view of a rotor core of a motor according to a fourth example embodiment of the present disclosure viewed from above.

FIG. 16 is a perspective view of the rotor core of the motor according to the fourth example embodiment of the present disclosure as viewed from the below.

FIG. 17 is a plan view of a connected laminate steel plate of the rotor core according to the fourth example embodiment of the present disclosure.

FIG. 18 is a perspective view of a rotor core of a motor according to a fifth example embodiment of the present disclosure as viewed from above.

FIG. 19 is a perspective view of the rotor core of the motor according to the fifth example embodiment of the present disclosure as viewed from below.

FIG. 20 is a plan view of a connected laminate steel plate of the rotor core according to the fifth example embodiment of the present disclosure.

FIG. 21 is a perspective view of a first modification of the rotor core according to the fifth example embodiment of the present disclosure as seen from above.

FIG. 22 is a perspective view of the first modification of the rotor core according to the fifth example embodiment of the present disclosure as seen from the below.

FIG. 23 is a longitudinal end view showing a first step of a manufacturing method of a second modification of the rotor core according to the fifth example embodiment of the present disclosure.

FIG. 24 is a longitudinal end view showing a second step of the manufacturing method of the rotor core according to the second modification of the fifth example embodiment of the present disclosure.

FIG. 25 is a longitudinal end view showing a third step of the manufacturing method of the second modification of the rotor core according to the fifth example embodiment of the present disclosure.

FIG. 26 is a perspective view of a rotor core of a motor according to a sixth example embodiment of the present disclosure as seen from above.

FIG. 27 is a perspective view of the rotor core of the motor according to the sixth example embodiment of the present disclosure as viewed from below.

FIG. 28 is a plan view of a first laminate steel plate of the rotor core according to the sixth example embodiment of the present disclosure.

FIG. 29 is a plan view of a second laminate steel plate of the rotor core according to the sixth example embodiment of the present disclosure.

FIG. 30 is a perspective view of a rotor of a motor according to a seventh example embodiment of the present disclosure.

FIG. 31 is a plan view of the rotor of the motor according to the seventh example embodiment of the present disclosure.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Hereinafter, example embodiments of the present disclosure will be described in detail with reference to the drawings. In the specification, a direction in which a rotational axis of a motor extends is simply referred to as an “axial direction,” a direction orthogonal to the rotational axis centering around the rotational axis of the motor is simply referred to as a “radial direction,” and a direction along an arc centering around the rotational axis of the motor is simply referred to as a “circumferential direction.” The central axis of the rotor core coincides with the rotational axis of the motor. Also, in the specification, for the sake of convenience of explanation, the axial direction is defined as a vertical direction, and a shape and a positional relationship of each part will be described with a depth direction of the sheet of FIG. 1 serving as the vertical direction of the rotor core, the rotor, and the motor. It should be noted that the definition in the vertical direction does not limit the direction when the motor is used. Also, in the specification, an end view parallel to the axial direction is referred to as a “longitudinal end view.” In addition, the terms “parallel” and “vertical” used in the specification do not mean technically parallel or vertical, but include substantially parallel and substantially vertical.

An overall configuration of a motor according to a first preferred embodiment of the present invention will be described. FIG. 1 is a plan view of a motor according to an preferred embodiment of the present invention. The motor 1 shown in FIG. 1 has a stator 2 and a rotor 3.

The stator 2 has, for example, a cylindrical or substantially cylindrical shape extending in the axial direction. The stator 2 is disposed with a predetermined gap provided radially outside the rotor 3. The stator 2 has a stator core 21, an insulator 22, and a coil 23.

The stator core 21 has a tubular or substantially tubular shape extending in the axial direction. The stator core 21 is formed by laminating a plurality of magnetic steel plates in the axial direction. The stator core 21 has a core back 21 a and teeth (not shown). The core back 21 a has an annular or substantially annular shape. The teeth extend radially inward from an inner circumferential surface of the core back 21 a. A plurality of teeth are arranged side by side at predetermined intervals in the circumferential direction.

The insulator 22 is provided to surround an outer surface of a tooth. The insulator 22 is disposed between the stator core 21 and the coil 23. The insulator 22 is made of, for example, an electrically insulating member made of a synthetic resin. The coil 23 is formed by winding a conductive wire around an outer circumference of the insulator 22.

The rotor 3 has a cylindrical or substantially cylindrical shape extending in the axial direction. The rotor 3 is positioned with a predetermined gap provided radially inside the stator 2. The rotor 3 has a shaft 31, a rotor core 40, magnets 32, and space portions 33 or resin portions 34. The space portions 33 have column portions 33 a and outer peripheral portions 33 b.

The shaft 31 is a rotational axis of the motor 1. The shaft 31 has a columnar or substantially columnar shape extending in a vertical direction. The shaft 31 is inserted into an upper bearing and a lower bearing (both not shown) provided on an upper side and a lower side of the rotor 3 and is rotatably supported thereon. The rotor 3 rotates around the shaft 31 extending in the vertical direction.

The rotor core 40 has a cylindrical or substantially cylindrical shape extending in the axial direction. The shaft 31 is inserted into hole portions 41 d and 42 d positioned at a radially central portion of the rotor core 40. The central axis of the rotor core 40 coincides with the shaft 31 of the motor 1. The rotor core 40 is formed by laminating, for example, a plurality of magnetic steel plates in the axial direction. Details of the rotor core 40 will be described later.

The magnet 32 is disposed radially inside an outer edge portion of the rotor core 40. A plurality of magnets 32 are arranged side by side at predetermined intervals in the circumferential direction. For example, eight magnets 32 are provided. The magnet 32 is a rectangular parallelepiped body having a substantially rectangular bottom surface and extending in the axial direction. An axial length of the magnet 32 substantially coincides with an axial length of the rotor core 40. The magnet 32 is supported by the rotor core 40.

The column portions 33 a are provided between the magnets 32 adjacent to each other in the circumferential direction. For example, when there are eight magnets 32, the column portions 33 a are provided at eight places. The column portion 33 a is a space of a quadrangular column or substantially quadrangular column shape whose bottom surface has a trapezoidal or substantially trapezoidal shape and extends in the axial direction. The column portion 33 a penetrates the rotor core 40 in the axial direction. By providing the column portion 33 a, it is possible to more effectively utilize magnetic flux of the magnet 32 in the rotor 3.

The outer peripheral portions 33 b are provided on outer sides in the radial direction of the column portions 33 a. The outer peripheral portions 33 b are provided at eight locations. The outer peripheral portions 33 b have substantially semicircular bottom surfaces and extend in the axial direction.

The resin portions 34 are provided in the space portions 33. The resin portions 34 are provided by pouring a synthetic resin, an adhesive, etc. into a space portion 33 surrounded by an outer circumferential surface of the rotor core 40 and an inner circumferential surface of a metal mold (not shown) disposed radially outside the rotor core 40 at an outer edge portion of the rotor 3. As a result, the resin portions 34 play a role as a flux barrier.

Subsequently, a detailed configuration of the rotor core 40 will be described. FIG. 2 is a perspective view of the rotor core of the motor 1 according to the first preferred embodiment of the present invention as viewed from above. FIG. 3 is a perspective view of the rotor core of the motor 1 according to the first preferred embodiment of the present invention as viewed from below. FIG. 4 is a plan view of a first laminate steel plate of the rotor core according to the first preferred embodiment of the present invention. FIG. 5 is a plan view of a second laminate steel plate of the rotor core according to the first preferred embodiment of the present invention.

The rotor core 40 shown in FIGS. 2 and 3 has first laminate steel plates 41 and second laminate steel plates 42. Each of the first laminate steel plates 41 and the second laminate steel plates 42 expands in the radial direction with respect to the central axis of the rotor core 40.

The first laminate steel plate 41 shown in FIG. 4 has a first base portion 41 a, a penetrating portion 41 b, and a piece portion 41 c.

The first base portion 41 a is positioned on a radially outer side of the central axis. An outer shape of the first base portion 41 a is substantially octagonal. At the radially central portion of the first base portion 41 a, there is a hole portion 41 d through which the shaft 31 penetrates in the axial direction.

The penetrating portion 41 b is provided on a radially outer side of each of eight edges of an outer edge portion 41 w of the first base portion 41 a. The penetrating portion 41 b is formed as a gap between the first base portion 41 a and the piece portion 41 c. The magnets 32 are provided one by one in the eight penetrating portions 41 b, respectively (see FIG. 1).

The piece portion 41 c is separately disposed on a radially outer side of the first base portion 41 a with the penetrating portion 41 b therebetween. The plurality of piece portions 41 c are disposed at predetermined intervals in the circumferential direction. For example, eight piece portions 41 c are provided radially outside the eight edges on the outer periphery of the first base portion 41 a, respectively. The center of the piece portion 41 c is shifted radially outward from the axis of the shaft 31 in its shape in a plan view, and the piece portion 41 c is in a semicircular or substantially semicircular shape which has an arc with a radius smaller than the radius of the rotor 3 and a straight portion corresponding to a string positioned on a radially inner side of the arc. The straight portion on the radially inner side of the piece portion 41 c is substantially parallel to the outer edge portion 41 w of the first base portion 41 a.

The first base portion 41 a has protruding portions 41 e. The protruding portions 41 e are provided in angular regions with respect to the central axis between the piece portions 41 c adjacent to each other in the circumferential direction. That is, the protruding portions 41 e are provided in fan-shaped regions surrounded by circumferentially opposed end portions of the circumferentially adjacent piece portions 41 c and the central axis, respectively. In other words, the protruding portions 41 e are provided on the column portions 33 a of the rotor 3. An preferred example of the fan-shaped angular region with respect to the central axis between the circumferentially adjacent piece portions 41 c is illustrated with a one-dot chain line in FIG. 4.

The protruding portion 41 e protrudes radially outward from the outer edge portion 41 w of the first base portion 41 a. When the first base portion 41 a is polygonal, the protruding portion 41 e protrudes radially outward from each apex of the first base portion 41 a. A protruding length of the protruding portion 41 e is shorter than a width of the penetrating portion 41 b in the radial direction. Since the first base portion 41 a has the protruding portion 41 e, when the magnet 32 is inserted between the first base portion 41 a and the piece portion 41 c, that is, the penetrating portion 41 b, circumferential end portions of the magnet 32 can be brought into contact with the protruding portions 41 e. Accordingly, it is possible to perform the positioning of the magnet 32 in the circumferential direction.

The second laminate steel plate 42 shown in FIG. 5 has a second base portion 42 a, penetrating portions 42 b, and annular portions 42 c.

The second base portion 42 a is positioned on a radially outer side of the central axis. An outer shape of the second base portion 42 a is substantially octagonal. The outer shape of the second base portion 42 a is substantially the same as the outer shape of the first base portion 41 a. In a central portion of the second base portion 42 a in the radial direction, there is a hole portion 42 d through which the shaft 31 penetrates in the axial direction.

The penetrating portion 42 b is provided on a radially outer side of each of eight edges on an outer periphery of the second base portion 42 a. The penetrating portion 42 b is formed as a gap between the second base portion 42 a and a large diameter portion 42 f of the annular portion 42 c which will be described later. The magnets 32 are provided one by one in eight penetrating portions 42 b, respectively (see FIG. 1).

The annular portion 42 c is separately disposed on a radially outer side of the second base portion 42 a with the penetrating portion 42 b therebetween. The annular portion 42 c extends in the circumferential direction. The annular portion 42 c has a shape similar to a shape obtained by connecting the eight piece portions 41 c of the first laminate steel plate 41 in an annular or substantially annular shape.

The annular portion 42 c has a large diameter portion 42 f and a small diameter portion 42 g which have different outer diameters. In the annular portion 42 c, the large diameter portion 42 f and the small diameter portion 42 g are alternately arranged in the circumferential direction. According to this configuration, magnetic saturation is likely to occur in the small diameter portion 42 g. Therefore, it is possible to efficiently guide the magnetic flux, so that and generation of the magnetic flux loop inside the rotor core 40 can be suppressed.

In the axial direction, the large diameter portion 42 f is disposed at the same position as the piece portion 41 of the first laminate steel plate 41. The large diameter portion 42 f has a cutout circular or substantially cutout circular shape similar to that of the piece portion 41 c in its shape in a plan view. The large diameter portion 42 f is provided on a radially outer side of each of eight edges of the outer periphery of the second base portion 42 a at eight positions, similarly to the piece portion 41 c. A straight portion on a radially inner side of the large diameter portion 42 f is substantially parallel to a side of the outer periphery of the second base portion 42 a. An outer diameter of the large diameter portion 42 f is larger than an outer diameter of the small diameter portion 42 g.

In the axial direction, the small diameter portion 42 g is disposed at the same position as a region between the piece portions 41 adjacent to each other in the circumferential direction of the first laminate steel plate 41. The small diameter portion 42 g has a long plate or substantially long plate shape connecting the large diameter portions 42 f adjacent in the circumferential direction in its shape in a plan view. The small diameter portion 42 g connects end portions of two large diameter portions 42 f to each other. The outer diameter of the small diameter portion 42 g is smaller than the outer diameter of the large diameter portion 42 f.

The small diameter portion 42 g has projections 42 h. The projections 42 h extend radially inward from an inner circumferential surface of the small diameter portion 42 g. According to this configuration, a strength of the annular portion 42 c can be improved. Further, when the magnet 32 is inserted between the second base portion 42 a and the annular portion 42 c, that is, the penetrating portion 42 b, circumferential end portions of the magnet 32 can be brought into contact with the projections 42 h. In this way, it is possible to perform positioning of the magnet 32 in the circumferential direction. Also, a radial length of the projection 42 h is shorter than a radial width of the penetrating portion 42 b.

For example, two projections 42 h are provided for one small diameter portion 42 g. The two projections 42 h provided in the one small diameter portion 42 g are arranged in a circumferentially separated manner. According to this configuration, it is possible to widely use the region between the two projections 42 h as a flux barrier. Therefore, it is possible to more effectively utilize the magnetic flux of the magnet. The number of the projections 42 h is not limited to two, and may be one or three or more.

The second base portion 42 a has protruding portions 42 e. The protruding portion 42 e are provided in angular regions with respect to the central axis where the small diameter portions 42 g are positioned. In the case where the second base portion 42 a is polygonal, the protruding portion 42 e protrudes radially outward from each apex of the second base portion 42 a. That is, the protruding portion 42 e is provided in a fan-shaped region surrounded by both circumferential end portions of the small diameter portion 42 g and the central axis. In other words, the protruding portion 42 e is provided on the column portion 33 a of the rotor 3. An example of the fan-shaped angular region with respect to the central axis where the small diameter portion 42 g is positioned is illustrated with a one-dot chain line in FIG. 5.

In addition, as described above, the small diameter portion 42 g is disposed at the same position as the region between the circumferentially adjacent piece portions 41 c of the first laminate steel plate 41 in the axial direction. Therefore, as far as the rotor core 40 is concerned, the protruding portion 42 e is provided in the angular region with respect to the central axis between the piece portions 41 c adjacent to each other in the circumferential direction.

The protruding portion 42 e protrudes radially outward from an outer edge portion 42 w of the second base portion 42 a. A tip portion of the protruding portion 42 e faces the radially inner side of the small diameter portion 42 g. The protruding portion 42 e is disposed in a region between the two projections 42 h with respect to the circumferential direction. A protruding length of the protruding portion 42 e is shorter than a width of the penetrating portion 42 b in the radial direction. In addition, the protruding portion 42 e does not come into contact with the two projections 42 h. Since the second base portion 42 a has the protruding portion 42 e, when the magnet 32 is inserted between the second base portion 42 a and the annular portion 42 c, that is, the penetrating portion 42 b, the circumferential end portions of the magnet 32 can be brought into contact with the protruding portions 42 e. Accordingly, it is possible to perform the positioning of the magnet 32 in the circumferential direction.

The rotor core 40 shown in FIGS. 2 and 3 is formed by laminating a plurality of first laminate steel plates 41 having the above structure and at least one second laminate steel plate 42 having the above structure in the axial direction. At this time, the piece portion 41 c of the first laminate steel plate 41 and the large diameter portion 42 f of the annular portion 42 c of the second laminate steel plate 42 overlap in the axial direction, and the first laminate steel plate 41 and the second laminate steel plate 42 are laminated at a position where their outer peripheral edges are partially aligned. The first laminate steel plate 41 and the second laminate steel plate 42 are fixed, for example, by caulking or the like.

According to this configuration, there is no region of a steel plate over the entire region in the circumferential direction between the first base portion 41 a of the first laminate steel plate 41 and the piece portion 41 c and between the second base portion 42 a and the annular portion 42 c of the second laminate steel plate 42. In this way, a flux barrier such as an air layer can be provided between the first base portion 41 a and the piece portion 41 c and between the second base portion 42 a and the annular portion 42 c. Therefore, it is possible to more effectively utilize the magnetic flux of the magnet 32.

Since the number of the second laminate steel plates 42 is smaller than the number of the first laminate steel plates 41, it is possible to suppress an amount of magnetic flux flowing through the annular portion 42 c of the entire rotor core 40 as compared to the case where the entire rotor core 40 is formed by the second laminate steel plates 42. Therefore, it is possible to more effectively utilize the magnetic flux of the magnet 32 in the annular portion 42 c.

More specifically describing with respect to the laminated structure of the first laminate steel plates 41 and the second laminate steel plates 42, for example, two pieces of second laminate steel plates 42 are disposed at the upper end and the lower end in the axial direction of the rotor core 40, and a plurality of first laminate steel plates 41 are disposed between the second laminate steel plate 42 at the upper end in the axial direction and the second laminate steel plate 42 at the lower end in the axial direction. According to this configuration, it is possible to improve the strength of the rotor core 40. Further, for example, two second laminate steel plates 42 are disposed also in a middle portion of the plurality of first laminate steel plates laminated in the axial direction. According to this configuration, it is possible to further improve the strength of the rotor core 40.

The rotor core 40 may have such a configuration in which the first laminate steel plate 41 is disposed at each of the upper end and the lower end in the axial direction, and a plurality of second laminate steel plates 42 are disposed between the first laminate steel plate 41 at the upper end in the axial direction and the first laminate steel plate 41 at the lower end in the axial direction. In this rotor core 40, each of the upper end and the lower end in the axial direction is the first laminate steel plate 41. The rotor core 40 may have a structure of a plurality of first laminate steel plates 41, one or two second laminate steel plates 42, and a plurality of first laminate steel plates 41 in order from the top. In addition, the rotor core 40 may have a structure of a plurality of first laminate steel plates 41, one or two second laminate steel plates 42, a plurality of first laminate steel plates 41, one or two second laminate steel plates 42, and a plurality of first laminate steel plates 41 in order from the top.

In the rotor core 40 where the second laminate steel plate 42 is disposed at each of the upper end and the lower end in the axial direction, when the axial length of the magnet 32 is shorter than the axial length of the rotor core 40 in the rotor core 40 where the second laminate steel plate 42 is disposed at each of the upper end and the lower end in the axial direction, it may be considered that the annular portion 42 c of the second laminate steel plate 42 positioned at the upper end is magnetically saturated and the annular portion 42 c of the second laminate steel plate 42 positioned at the lower end is not magnetically saturated. At that time, there is a possibility that a difference in distortion amount occurs between an upper end portion and a lower end portion of a back electromotive voltage waveform in the coil 23 depending on presence or absence of magnetic saturation in the annular portions 42 c at the upper end and the lower end. Therefore, by not providing the second laminate steel plate 42 at the upper end and the lower end of the rotor core 40, distortion of the back electromotive voltage waveform can be suppressed. Instead, by adopting a configuration in which a plurality of second laminate steel plates 42 are disposed between the first laminate steel plate 41 at the upper end in the axial direction and the first laminate steel plate 41 at the lower end in the axial direction, it is possible to prevent the first base portion 41 a and the piece portion 41 c from being separated from each other and the second base portion 42 a and the annular portion 42 c from being separated while effectively utilizing the magnetic flux of the magnet 32.

In the rotor 3 of the first preferred embodiment, by pressing the annular portion 42 c of the second laminate steel plate 42 from the radially outer side, the magnet 32 can be held. Thus, the magnet can be held without providing the resin portion 34, so that the number of man-hours and materials can be reduced. Further, by pressing the small diameter portion 42 g of the annular portion 42 c, the column portion 33 a can be eliminated. This makes it possible to hold the magnet more firmly and to make more effective use of the magnetic flux.

Next, a motor according to a second preferred embodiment of the present invention will be described. FIG. 6 is a perspective view of a rotor core of the motor according to the second preferred embodiment of the present invention as viewed from above. FIG. 7 is a perspective view of the rotor core of the motor according to the second preferred embodiment of the present invention as viewed from below. FIG. 8 is a plan view of a connected laminate steel plate of the rotor core according to a second preferred embodiment of the present invention. Also, since a basic configuration of this preferred embodiment is the same as that of the first preferred embodiment described above, constituent elements common to the first preferred embodiment are denoted by the same reference numerals or the same names as before, explanation thereof may be omitted.

The rotor core 40 shown in FIGS. 6 and 7 has a connected laminate steel plate 43 in addition to the first laminate steel plate 41 and the second laminate steel plate 42. Similarly to the first laminate steel plate 41 and the second laminate steel plate 42, the connected laminate steel plate 43 expands in the radial direction with respect to the central axis of the rotor core 40.

The connected laminate steel plate 43 shown in FIG. 8 has a connected base portion 43 a, penetrating portions 43 b, connected annular portions 43 c, and connecting portions 43 k.

The connected base portion 43 a, the penetrating portion 43 b, and the connected annular portion 43 c have the same configuration as the second base portion 42 a, the penetrating portion 42 b, and the annular portion 42 c of the second laminate steel plate 42, respectively. That is, the connected base portion 43 a has a hole portion 43 d and protruding portions 43 e. The penetrating portion 43 b is formed as a gap between the connected base portion 43 a and a large diameter portion 43 f of the connected annular portion 43 c. The connected annular portion 43 c has the large diameter portion 43 f and a small diameter portion 43 g which are different in outer diameter and are arranged alternately in the circumferential direction.

In addition, in this preferred embodiment, the protruding portion 43 e of the connected laminate steel plate 43 is enlarged toward both circumferential sides more than the protruding portion 41 e of the first laminate steel plate 41 and the protruding portion 42 e of the second laminate steel plate 42. Also, a part of the protruding portion 43 e of the connected laminate steel plate 43 overlaps the penetrating portion 41 b of the first laminate steel plate 41 and the penetrating portion 42 b of the second laminate steel plate 42. As a result, the magnet 32 inserted into the penetrating portion 41 b and the penetrating portion 42 b is caught by the protruding portion 43 e. Therefore, it is possible to prevent the magnet 32 from downwardly falling off the rotor core 40.

The connecting portions 43 k are disposed in regions between the connected base portion 43 a and the connected annular portions 43 c in the radial direction. The connecting portions 43 k are disposed at predetermined intervals in the circumferential direction. The connecting portions 43 k are disposed in regions between the adjacent penetrating portions 43 b in the circumferential direction. The connecting portion 43 k has an elongated plate or substantially elongated plate shape extending in the radial direction in its shape in a plan view. The connecting portion 43 k connects the connected base portion 43 a and the connected annular portion 43 c. More specifically, the connecting portion 43 k connects a radially front end portion of the protruding portion 43 e and an inner edge portion of the small diameter portion 43 g.

The small diameter portion 43 g has two coupling portions 43 m. The coupling portions 43 m are provided adjacent to both circumferential sides of the connecting portion 43 k. That is, the small diameter portion 43 g has two coupling portions 43 m circumferentially adjacent to one connecting portion 43 k connected to the inner edge portion thereof. The coupling portion 43 m is connected to the large diameter portion 43 f on a side opposite to a region connected to the connecting portion 43 k.

In the rotor core 40 shown in FIG. 6 and FIG. 7, for example, one connected laminate steel plate 43 is disposed at the lower end in the axial direction. At this time, the piece portion 41 c of the first laminate steel plate 41, the large diameter portion 42 f of the annular portion 42 c of the second laminate steel plate 42, and the large diameter portion 43 f of the connected annular portion 43 c of the connected laminate steel plate 43 overlap in the axial direction, and the first laminate steel plate 41, the second laminate steel plate 42 and the connected laminate steel plate 43 are laminated at a position where their outer edge portions are partially aligned.

According to this configuration, it is possible to further improve the strength of the rotor core 40. Furthermore, it is possible to prevent the first base portion 41 a and the piece portion 41 c from being separated from each other, and the second base portion 42 a and the annular portion 42 c from being separated.

The connected laminate steel plate 43 may be disposed at the upper end in the axial direction of the rotor core 40. Further, the connected laminate steel plates 43 may be disposed at both the lower end and the upper end in the axial direction of the rotor core 40. According to this configuration, it is possible to further increase the strength of the rotor core 40. In addition, the connected laminate steel plate 43 at the upper end and the connected laminate steel plate 43 at the lower end may have different shapes. For example, the upper end may be a connected laminate steel plate 43 having penetrating portions through which the magnets 32 are inserted, and the lower end may be a connected laminate steel plate 43 for preventing the magnets 32 from falling off.

Next, a motor according to a third preferred embodiment of the present invention will be described. FIG. 9 is a partial enlarged plan view of a connected laminate steel plate of a rotor core according to a third preferred embodiment of the present invention. Also, since a basic configuration of this embodiment is the same as that of the first and second preferred embodiments described above, constituent elements common to those preferred embodiments are denoted by the same reference numerals or the same names as before and the explanation thereof may be omitted.

The rotor core 40 of the third preferred embodiment has a configuration in which, in the small diameter portion 43 g of the connected laminate steel plate 43 shown in FIG. 9, two coupling portions 43 m circumferentially adjacent to one connecting portion 43 k are cut from the large diameter portion 43 f. The coupling portions 43 m are cut inward from a radially outer side of the connected laminate steel plate 43 with respect to the connected laminate steel plates 43 which are laminated. Therefore, the rotor core 40 of the third preferred embodiment has a structure in which laminate steel plates obtained by cutting the coupling portions 43 m of the connected laminate steel plate 43 are laminated in the axial direction.

The coupling portion 43 m is cut at a position close to the large diameter portion 43 f. The coupling portion 43 m is bent inward in the radial direction. The bent coupling portion 43 m is adjacent to the penetrating portion 43 b side of the connecting portion 43 k.

Next, a manufacturing method of the rotor core 40, which is a motor core, will be described with reference to FIGS. 10 and 11. FIG. 10 is a perspective view showing an preferred example of a cutting device used in the manufacturing method of the rotor core according to the third preferred embodiment of the present invention. FIG. 11 is a partial enlarged plan view showing an preferred example of a cutting tool used in the manufacturing method of the rotor core according to the third preferred embodiment of the present invention.

The manufacturing method of the rotor core 40 of the third preferred embodiment includes a process of laminating the connected laminate steel plates 43 in the axial direction. In this process, the connected laminate steel plates 43 are laminated from the upper end to the lower end in the axial direction. In this way, the rotor core 40 of the third preferred embodiment is formed only by the laminate steel plates in which the coupling portions 43 m of the connected laminate steel plate 43 is cut. Also, in the process including the connected laminate steel plates 43, the first laminate steel plates 41, the second laminate steel plates 42, and the like may be laminated in combination.

Next, the manufacturing method of the rotor core 40 of the third preferred embodiment includes a process of cutting the coupling portions 43 m. In this process, for example, a cutting device 100 shown in FIG. 10 is used.

The cutting device 100 includes a pedestal portion 101, a pressing member 102, and a cutting tool 103. The rotor core 40 is placed on an upper surface of the pedestal portion 101 with the axial direction being substantially vertical. A pressing member 102 is disposed above the rotor core 40. The pressing member 102 holds the rotor core 40 between itself and the upper surface of the pedestal portion 101.

The cutting tool 103 is disposed on a radially outer side of the rotor core 40 disposed on the upper surface of the pedestal portion 101. The cutting tool 103 can move in the radial direction of the rotor core 40. The cutting tool 103 can press and abut its tip portion facing the outer circumferential surface of the rotor core 40 against the outer circumferential surface of the rotor core 40.

The cutting tool 103 has blade portions 103 a shown in FIG. 11 at a tip portion opposed to the outer circumferential surface of the rotor core 40. The blade portions 103 a extend in the axial direction of the rotor core 40.

The blade portions 103 a are provided at two locations separated in the circumferential direction. Each of the two blade portions 103 a has a corner portion 103 b and a flat portion 103 c on an outer surface on its circumferentially outer side. The two blade portions 103 a cut the two coupling portions 43 m from the large diameter portion 43 f by using the corner portion 103 b and the flat portion 103 c, respectively.

Since the manufacturing method of the rotor core 40 of the third preferred embodiment includes the process of cutting the coupling portions 43 m of the connected laminate steel plate 43, it is possible to eliminate the state in which the large diameter portions 43 f of the connected annular portions 43 c adjacent to each other in the circumferential direction are connected in the circumferential direction via the small diameter portions 43 g. Thus, the leakage of the magnetic flux that may occur at the coupling portion 43 m before cutting can be suppressed. Therefore, it is possible to suppress occurrence of a magnetic loop in the rotor core 40.

In the process of cutting the coupling portion 43 m, the connected laminate steel plate 43 is cut from the outer side to the inner side in the radial direction. According to this configuration, the coupling portion 43 m of the connected annular portion 43 c can be cut using the cutting device 100 without requiring a high-power pressing device. Therefore, it is possible to suppress the increase in size and cost of a manufacturing device of the rotor core 40.

In the conventional manufacturing method of punching a laminate steel plate in the axial direction, an additional process such as a half-punching process or the like is necessary in advance. On the other hand, the manufacturing method according to the modification of the rotor core 40 of the second preferred embodiment can be formed into a desired shape without requiring an additional process.

Further, in the conventional manufacturing method of punching a laminate steel plate in the axial direction, there is a possibility that sags or burrs may occur in the laminate steel plated at a lower end in the axial direction of the rotor core. On the other hand, in the manufacturing method according to the modification of the rotor core 40 of the second preferred embodiment, the cutting is performed from the radially outer side. Thus, the cutting distance required for the cutting becomes short in the laminate steel plate at a lower end of the rotor core 40 in the axial direction, so that occurrence of sags and burrs can be prevented.

Next, the manufacturing method of the rotor core 40 of the third preferred embodiment may include a process of removing the connecting portion 43 k. With this, occurrence of magnetic saturation that may occur at the connecting portion 43 k before removal can be suppressed. Therefore, it is possible to effectively suppress occurrence of a magnetic loop in the rotor core 40.

The configuration of the cutting device 100 described with reference to FIGS. 10 and 11 is an preferred example, and other configurations may be adopted as long as the connected laminate steel plate 43 can be cut from the outer side to the inner side in the radial direction.

Next, a first preferred example of the cutting process in the manufacturing method of the rotor core 40 will be described with reference to FIG. 12. FIG. 12 is a partial enlarged plan view of the connected laminate steel plate showing the first preferred example of the cutting process in the manufacturing method of the rotor core according to the third preferred embodiment of the present invention.

In the manufacturing method of the rotor core 40 of the third preferred embodiment, the first preferred example of the process of cutting the coupling portion 43 m uses the cutting tool 103 shown in FIG. 11. In this cutting process shown in FIG. 12, coupling portions 43 m at two locations circumferentially adjacent to one connecting portion 43 k are simultaneously cut. As shown in FIG. 9, the coupling portions 43 m cut at the two locations are bent inward in the radial direction.

First, two coupling portions 43 m are simultaneously cut and bent. Next, the rotor core 40 is rotated around the central axis by the angle between the connecting portions 43 k adjacent to each other in the circumferential direction. Subsequently, two coupling portions 43 m circumferentially adjacent to the next one connecting portion 43 k are simultaneously cut and bent. Subsequently, the cutting and bending of two coupling portions 43 m and the rotation of the rotor core 40 are repeated over the entire outer edge portion of the rotor core 40.

According to this method, since the two coupling portions 43 m are simultaneously cut, it is possible to minimize deformation of the rotor core 40, in particular, deformation of the connecting portion 43 k which may occur at the time of cutting. Further, at the time of cutting, it is possible to cut while holding one connecting portion 43 k disposed between two adjacent coupling portions 43 m. Thus, the efficiency of the cutting operation can be improved.

Next, a second preferred example of the cutting process in the manufacturing method of the rotor core 40 will be described with reference to FIG. 13. FIG. 13 is a plan view of the connected laminate steel plate showing the second preferred example of the cutting process of the manufacturing method of the rotor core 40 according to the third preferred embodiment of the present invention.

In the manufacturing method of the rotor core 40 of the third preferred embodiment, a cutting tool 104 having only one blade portion 103 a is used (see FIG. 13). In this cutting process shown in FIG. 13, coupling portions 43 m of a connected annular portion 43 c located at two locations on circumferentially inner sides with respect to two connecting portions 43 k adjacent to each other in the circumferential direction are simultaneously cut. The cut coupling portions 43 m at the two locations are bent, for example, radially inward.

First, two coupling portions 43 m are simultaneously cut and bent. Next, the rotor core 40 is rotated around the central axis by the angle between connecting portions 43 k adjacent to each other in the circumferential direction. Subsequently, two coupling portions 43 m located on the circumferentially inner sides with respect to the next two connecting portions 43 k adjacent to each other in the circumferential direction are cut and bent at the same time. Subsequently, the cutting and bending of two coupling portions 43 m and the rotation of the rotor core 40 are repeated over the entire outer edge portion of the rotor core 40.

According to this method, since the two coupling portions 43 m are simultaneously cut, it is possible to minimize deformation of the rotor core 40, in particular, deformation of the connecting portion 43 k which may occur at the time of cutting. In addition, it is possible to equalize the shape and size of the large diameter portion 43 f of the connected annular portion 43 c, which is a region between the two connecting portions 43 k adjacent to each other in the circumferential direction.

Next, a third preferred example of the cutting process in the manufacturing method of the rotor core 40 will be described with reference to FIG. 14. FIG. 14 is a plan view of a connected laminate steel plate showing a third preferred example of the cutting process in the manufacturing method of the rotor core according to the third preferred embodiment of the present invention.

In the manufacturing method of the rotor core 40 of the third preferred embodiment, a cutting tool 104 having only one blade portion 103 a is used (see FIG. 14). In this cutting process shown in FIG. 14, coupling portions 43 m disposed at two locations on sides opposite to each other with the central axis located therebetween are simultaneously cut. The coupling portions 43 m at the two locations are bent, for example, radially inward.

First, two coupling portions 43 m are simultaneously cut and bent. Next, the rotor core 40 is rotated around the central axis by the angle between the connecting portions 43 k adjacent to each other in the circumferential direction. Subsequently, the next two coupling portions 43 m disposed on sides opposite to each other with the central axis located therebetween are simultaneously cut and bent. Subsequently, the cutting and bending of two coupling portions 43 m and the rotation of the rotor core 40 are repeated over the entire outer edge portion of the rotor core 40.

According to this method, since two coupling portions 43 m are simultaneously cut, it is possible to minimize deformation of the rotor core 40, in particular, deformation of the connecting portion 43 k which may occur at the time of cutting.

The cutting process used in the third preferred embodiment is not limited to the rotor core as long as it is a motor core, and it may be adopted for a stator core. For example, a process of cutting toward a slot provided in a stator core may be considered.

Next, a motor according to a fourth preferred embodiment of the present invention will be described. FIG. 15 is a perspective view of a rotor core of the motor according to the fourth preferred embodiment of the present invention as viewed from above. FIG. 16 is a perspective view of the rotor core of the motor according to the fourth preferred embodiment of the present invention as viewed from below. FIG. 17 is a plan view of a connected laminate steel plate of the rotor core according to the fourth preferred embodiment of the present invention. Since a basic configuration of this preferred embodiment is the same as that of the first and second preferred embodiments described above, constituent elements common to those preferred embodiments are denoted by the same reference numerals or same names as before, and explanation thereof may be omitted.

The rotor core 40 shown in FIGS. 15 and 16 has a connected laminate steel plate 44 in addition to the first laminate steel plates 41 and the second laminate steel plates 42. Similarly to the first laminate steel plate 41 and the second laminate steel plate 42, the connected laminate steel plate 44 expands in the radial direction with respect to the central axis of the rotor core 40.

The connected laminate steel plate 44 shown in FIG. 17 has a connected base portion 44 a, penetrating portions 44 b, connected piece portions 44 c, and connecting portion 44 k.

The connected base portion 44 a has recessed portions 44 e. The recessed portions 44 e are provided in angular regions with respect to the central axis between the connected piece portions 44 c adjacent to each other in the circumferential direction. That is, the recessed portions 44 e are provided in fan-shaped regions surrounded by circumferentially opposed end portions of circumferentially adjacent connected piece portions 44 c and the central axis, respectively. In other words, the recessed portions 44 e are provided in the column portions 33 a of the rotor 3. An preferred example of the fan-shaped angular region with respect to the center axis between the circumferentially adjacent connected piece portions 44 c is illustrated with a one-dot chain line in FIG. 17.

The recessed portion 44 e is recessed radially inward from an outer edge portion 44 w of the connected base portion 44 a. When the connected base portion 44 a is polygonal, the recessed portion 44 e is recessed radially inward from each apex of the connected base portion 44 a. Since the connected base portion 44 a has the recessed portions 44 e, when a synthetic resin, adhesive or the like is poured on radially outer sides of the first base portion 41 a, the second base portion 42 a and the connected base portion 44 a after inserting the magnets 32 into the penetrating portions 41 b and 42 b, the synthetic resin, adhesive, etc. enter the recessed portions 44 e. Thus, it is possible to firmly fix the connected piece portions 44 c and the magnets 32.

The penetrating portion 44 b is formed as a gap between the connected base portion 44 a and the connected piece portion 44 c. Connecting portions 44 k are provided on both circumferential sides of the penetrating portion 44 b. The connecting portion 44 k overlaps the penetrating portion 41 b of the first laminate steel plate 41 and the penetrating portion 42 b of the second laminate steel plate 42. As a result, the magnet 32 inserted into the penetrating portion 41 b and the penetrating portion 42 b is caught by the connecting portion 44 k. Therefore, it is possible to prevent the magnet 32 from downwardly falling off the rotor core 40.

The connected piece portion 44 c is separately disposed on a radially outer side of the connected base portion 44 a with the penetrating portion 44 b therebetween. The separation mentioned here includes a form in which the connected piece portion 44 c and the connected base portion 44 a are partially connected by the connecting portion 44 k. For example, eight connected piece portions 44 c are disposed at predetermined intervals in the circumferential direction. The center of the connected piece portion 44 c is shifted radially outward from the axis of the shaft 31 in its shape in a plan view, and the connected piece portion 44 c is in a semicircular or substantially semicircular shape which has an arc having a radius smaller than the radius of the rotor 3 and a straight portion corresponding to a string positioned on the radially inner side of the arc. The straight portion on the radially inner side of the connecting piece portion 44 c is substantially parallel to the outer edge portion 44 w of the connected base portion 44 a.

The connecting portions 44 k are disposed in regions between the connected base portion 44 a and the connected piece portions 44 c in the radial direction. The connecting portions 44 k are provided on circumferential end portions of the connected piece portion 44 c with respect to one connected piece portion 44 c, respectively, and extend in parallel to each other. The connecting portions 44 k have an elongated plate or substantially elongated plate shape extending in a substantially radial direction in their shape in a plan view. The connecting portions 44 k connect the connected base portion 44 a and the connected piece portions 44 c. More specifically, the connecting portions 44 k connect both circumferential side regions of the recessed portion 44 e and straight portions of the connecting piece portions 44 c at both circumferential ends.

In the rotor core 40 shown in FIGS. 15 and 16, for example, two second laminate steel plates 42 are disposed at the upper end and a lower portion in the axial direction, and a plurality of first laminate steel plates 41 are disposed between the second laminate steel plate 42 at the upper end in the axial direction and the second laminate steel plate 42 at the lower portion in the axial direction. For example, two second laminate steel plates 42 are disposed also in a middle portion of the plurality of first laminate steel plates 41 laminated in the axial direction. Further, for example, one connected laminate steel plate 44 is disposed at the lower end in the axial direction. At this time, the piece portion 41 c of the first laminate steel plate 41, the large diameter portion 42 f of the annular portion 42 c of the second laminate steel plate 42, and the connected piece portion 44 c of the connected laminate steel plate 44 overlap in the axial direction, and the first laminate steel plate 41, the second laminate steel plate 42 and the connected laminate steel plate 44 are laminated at a position where their outer peripheral edges are partially aligned.

According to this configuration, it is possible to further improve the strength of the rotor core 40. In addition, when the magnet 32 is inserted into the penetrating portions 41 b and 42 b, the magnet 32 is caught by the connecting portions 44 k in the axial direction. This makes it possible to prevent the magnet 32 from falling off the rotor core 40. Furthermore, it is possible to prevent the first base portion 41 a and the piece portions 41 c from being separated from each other, and the second base portion 42 a and the annular portions 42 c from being separated.

The connected laminate steel plate 44 may be disposed at the upper end in the axial direction of the rotor core 40. Also, the connected laminate steel plates 44 may be disposed at both the lower end and the upper end in the axial direction of the rotor core 40. According to this configuration, it is possible to further increase the strength of the rotor core 40. Further, the upper connected laminate steel plate 44 and the lower connected laminate steel plate 44 may have different shapes. For example, the upper end may be a connected laminate steel plate 44 having penetrating portions through which the magnets 32 are inserted, and the lower end may be a connected laminate steel plate 44 for preventing the magnets 32 from falling off.

In the rotor core 40, the first laminate steel plate 41 has the protruding portion 41 e, the second laminate steel plate 42 has the protruding portion 42 e, and the connected laminate steel plate 44 has the recessed portion 44 e. The magnet 32 can be brought into contact with the protruding portions 41 e and 42 e when the magnet 32 is inserted into the penetrating portions 41 b and 42 b. Accordingly, the positioning of the magnet 32 can be performed in the circumferential direction. Further, when a synthetic resin, an adhesive or the like is poured on a radially outer side of the first base portion 41 a or the like after inserting the magnet 32 into the penetrating portions 41 b and 42 b, the synthetic resin, adhesive or the like intrudes into the recessed portions 44 e. Thus, the magnet 32 can be firmly fixed. Therefore, it is possible to realize both positioning of the magnet 32 and firm fixation of the magnet 32.

Next, a motor according to a fifth preferred embodiment of the present invention will be described. FIG. 18 is a perspective view of a rotor core of the motor according to the fifth preferred embodiment of the present invention as viewed from above. FIG. 19 is a perspective view of the rotor core of the motor according to the fifth preferred embodiment of the present invention as viewed from below. FIG. 20 is a plan view of a connected laminate steel plate of the rotor core according to the fifth preferred embodiment of the present invention. Since a basic configuration of this preferred embodiment is the same as the first, second and third preferred embodiments described above, constituent elements common to those preferred embodiments are denoted by the same reference numerals or same names as before, and explanation thereof may be omitted.

The rotor core 40 shown in FIGS. 18 and 19 has a connected laminate steel plate 45 in addition to the first laminate steel plate 41 and the second laminate steel plate 42. Similarly to the first laminate steel plate 41 and the second laminate steel plate 42, the connected laminate steel plate 45 expands in the radial direction with respect to the central axis of the rotor core 40.

The connected laminate steel plate 45 shown in FIG. 20 has a connected base portion 45 a, penetrating portions 45 b, connected piece portions 45 c, and connecting portions 45 k.

The connected base portion 45 a, the penetrating portion 45 b, and the connected piece portion 45 c have the same configuration as the connected base portion 44 a, the penetrating portion 44 b and the connecting piece portion 44 c of the connected laminate steel plate 44 of the fourth preferred embodiment. That is, the connected base portion 45 a has a hole portion 45 d and recessed portions 45 e.

The penetrating portion 45 b is configured as a gap between the connected base portion 45 a and the connected piece portion 45 c. The connecting portions 45 k are provided on both circumferential sides of the penetrating portion 45 b. The connecting portions 45 k overlap the penetrating portion 41 b of the first laminate steel plate 41 and the penetrating portion 42 b of the second laminate steel plate 42. As a result, the magnet 32 inserted into the penetrating portion 41 b and the penetrating portion 42 b is caught by the connecting portions 45 k. Therefore, it is possible to prevent the magnet 32 from downwardly falling off the rotor core 40.

The connected piece portion 45 c is separately disposed on a radially outer side of the connected base portion 45 a with the penetrating portion 45 b therebetween. The separation mentioned here includes a form in which the connected piece portion 45 c and the connected base portion 45 a are partially connected by the connecting portion 45 k. For example, eight connected piece portions 45 c are disposed at predetermined intervals in the circumferential direction. The center of the connected piece portion 45 c is shifted radially outward from the axis of the shaft 31 in its shape in a plan view, and the connected piece portion 45 c is in a semicircular or substantially semicircular shape which has an arc having a radius smaller than the radius of the rotor 3 and a straight portion corresponding to a string positioned on the radially inner side of the arc. The straight portion on the radially inner side of the connecting piece portion 45 c is substantially parallel to an outer edge portion 45 w of the connected base portion 45 a.

The connecting portions 45 k are disposed in regions between the connected base portion 45 a and the connected piece portions 45 c in the radial direction. The connecting portions 45 k are provided at two locations inward from circumferential end portions of the connected piece portion 45 c with respect to one straight portion of the connected piece portion 45 c, and extend in parallel to each other. The connecting portions 45 k connect the outer edge portion 45 w of the connected base portion 45 a and the straight portion of the connected piece portion 45 c. The connecting portions 45 k have an elongated plate or substantially elongated plate shape extending in a radial or substantially radial direction in their shape in a plan view.

In the rotor core 40 shown in FIGS. 18 and 19, for example, two second laminate steel plates 42 are disposed at the upper end and a lower portion in the axial direction, and a plurality of first laminate steel plates 41 are disposed between the second laminate steel plate 42 at the upper end in the axial direction and the second laminate steel plate 42 at the lower portion in the axial direction. For example, two second laminate steel plates 42 are disposed also in a middle portion of the plurality of first laminate steel plates 41 laminated in the axial direction. Further, for example, one connected laminate steel plate 45 is disposed at the lower end in the axial direction. At this time, the piece portion 41 c of the first laminate steel plate 41, the large diameter portion 42 f of the annular portion 42 c of the second laminate steel plate 42, and the connected piece portion 45 c of the connected laminate steel plate 45 overlap in the axial direction, and the first laminate steel plate 41, the second laminate steel plate 42 and the connected laminate steel plate 45 are laminated at a position where their outer edge portions are partially aligned.

According to this configuration, it is possible to further improve the strength of the rotor core 40. Further, when the magnet 32 is inserted into the penetrating portions 41 b and 42 b, the magnet 32 is caught by the connecting portions 45 k in the axial direction. This makes it possible to prevent the magnet 32 from falling off the rotor core 40. Furthermore, it is possible to prevent the first base portion 41 a and the piece portion 41 c from being separated from each other, and the second base portion 42 a and the annular portion 42 c from being separated.

In addition, the connected laminate steel plate 45 may be disposed at the upper end in the axial direction of the rotor core 40. Also, the connected laminate steel plates 45 may be disposed at both the lower end and the upper end in the axial direction of the rotor core 40. According to this configuration, it is possible to further increase the strength of the rotor core 40. Further, the connected laminate steel plate 45 at the upper end and the connected laminate steel plate 45 at the lower end may have different shapes. For example, the upper end may be a connected laminate steel plate 45 having penetrating portions through which the magnets 32 are inserted, and the lower end may be a connected laminate steel plate 45 for preventing the magnets 32 from falling off.

Also, in the rotor core 40, the first laminate steel plate 41 has the protruding portion 41 e, the second laminate steel plate 42 has the protruding portion 42 e, and the connected laminate steel plate 45 has the recessed portion 45 e. The magnet 32 can be brought into contact with the protruding portions 41 e and 42 e when the magnet 32 is inserted into the penetrating portions 41 b and 42 b. Accordingly, the positioning of the magnet 32 can be performed in the circumferential direction. Further, when a synthetic resin, an adhesive or the like is poured on a radially outer side of the first base portion 41 a or the like after inserting the magnet 32 into the penetrating portions 41 b and 42 b, the synthetic resin, adhesive or the like intrudes into the recessed portions 45 e. Thus, the magnet 32 can be firmly fixed. Therefore, it is possible to realize both positioning of the magnet 32 and firm fixation of the magnet 32.

Subsequently, a first modification of the rotor core 40 of the fifth preferred embodiment will be described. FIG. 21 is a perspective view of the first modification of the rotor core according to the fifth preferred embodiment of the present invention as seen from above. FIG. 22 is a perspective view of the first modification of the rotor core according to the fifth preferred embodiment of the present invention as viewed from the below.

In the first modification of the rotor core 40 of the fifth preferred embodiment, the rotor core 40 shown in FIGS. 21 and 22 has a connected laminate steel plate 45 in addition to the first laminate steel plate 41 and the second laminate steel plate 42. The connected laminate steel plate 45 is disposed at the lower end in the axial direction of the rotor core 40.

As shown in FIG. 22, the connected laminate steel plate 45 has connecting portions 45 k as an intervening portion interposed between the connected base portion 45 a and the connected piece portion 45 c. Also, the intervening portion mentioned here includes, in addition to the connecting portion 45 k, an outward projection provided in the connected base portion 45 a, an inward projection provided in the connected piece portion 45 c, and a configuration in which a space between the connected base portion 45 a and the connected piece portion 45 c is filled with a steel plate member.

According to this configuration, the magnet 32 inserted into the penetrating portion 41 b and the penetrating portion 42 b is caught by the intervening portion at the lower portion of the rotor core 40. Therefore, it is possible to prevent the magnet 32 from downwardly falling off the rotor core 40. Further, since the connected base portion 45 a and the connected piece portion 45 c are connected via the connecting portions 45 k, it is possible to prevent the first base portion 41 a and the piece portion 41 c from being separated from each other and the second base portion 42 a and the annular portion 42 c from being separated.

As shown in FIG. 21, the second laminate steel plate 42 disposed at the axially upper end of the rotor core 40 has outward projections 42 n. The outward projections 42 n extend radially outward from the outer edge portion 42 w of the second base portion 42 a. A projecting length of the outward projection 42 n is shorter than the radial width of the penetrating portion 42 b. The magnet 32 is inserted into the penetrating portion 41 b and the penetrating portion 42 b below the second laminate steel plate 42 disposed at the axially upper end of the rotor core 40.

According to this configuration, the magnet 32 is caught by the outward projections 42 n at the upper portion of the rotor core 40. Therefore, it is possible to prevent the magnet 32 from upwardly coming out of the rotor core 40.

Subsequently, a second modification of the rotor core 40 of the fifth preferred embodiment will be described. FIG. 23 is a longitudinal end view showing a first step of the manufacturing method of the second modification of the rotor core according to the fifth preferred embodiment of the present invention. FIG. 24 is a longitudinal end view showing a second step of the manufacturing method of the second modification of the rotor core according to the fifth preferred embodiment of the present invention. FIG. 25 is a longitudinal end view showing a third step of the manufacturing method of the second modification of the rotor core according to the fifth preferred embodiment of the present invention.

In the second modification of the rotor core 40 of the fifth preferred embodiment, the connected laminate steel plate 45 is disposed at the upper end in the axial direction of the rotor core 40. Alternatively, in the second modification of the rotor core 40 of the fifth preferred embodiment, the connected laminate steel plate 45 is disposed at both the upper end and the lower end in the axial direction of the rotor core 40.

As shown in FIG. 25, the connecting portions 45 k of the connected laminate steel plate 45 at the axially upper end is cut inward from the axially upper side of the connected laminate steel plate 45 with respect to the connected laminate steel plate 45 that is laminated. The cut connecting portions 45 k are bent toward the inside of the penetrating portion 45 b. In this way, by cutting the connecting portions 45 k, the outward projections 45 n can be formed. Also, inward projections may be formed by a similar cutting process.

The manufacturing method of the second modification of the rotor core 40 of the fifth preferred embodiment includes a process of laminating divided laminate steel plates in the axial direction. The divided laminate steel plate corresponds to the first laminate steel plate 41 in which the first base portion 41 a and the piece portion 41 c are divided in the radial direction. In this process, a plurality of first laminate steel plates 41 are laminated in the axial direction. In addition, the rotor core 40 also includes a plurality of second laminate steel plates 42 having a smaller number of laminated layers than the first laminate steel plates 41.

Next, the manufacturing method according to the second modification of the rotor core 40 of the fifth preferred embodiment includes a process of further laminating the connected laminate steel plate 45 to the first laminate steel plates 41 that ate laminated. In this process, the connected laminate steel plate 45, in which the connected base portion 45 a and the connected piece portion 45 c are connected via the connecting portions 45 k, is laminated on the axially upper end of the first laminate steel plates 41 that are laminated. Further, in the manufacturing method of the second modification of the rotor core 40 of the fifth preferred embodiment, the connected laminate steel plate 45 (a intervened laminate steel plate) in which the connecting portions 45 k as an intervening portion are interposed between the connected base portion 45 a and the connected piece portion 45 c is laminated on the axially lower end of the first laminate steel plates 41 that are laminated. In these lamination processes, the piece portion 41 c of the first laminate steel plate 41 and the connected piece portion 45 c of the connected laminate steel plate 45 overlap in the axial direction, and the first laminate steel plate 41 and the connected laminate steel plate 45 are laminated at a position where their outer edge portions are partially aligned.

Next, the manufacturing method of the second modification of the rotor core 40 of the fifth preferred embodiment includes a process of cutting the connecting portions 45 k with a cutting member 200. In this process, the cutting member 200 is inserted into the penetrating portion 45 b (not shown) of the connected laminate steel plate 45 shown in FIGS. 23, 24, and 25 to cut the connecting portions 45 k with the cutting member 200. In this way, it is possible to eliminate the state in which the connected base portion 45 a and the connected piece portion 45 c are connected. Therefore, a flux barrier such as an air layer can be provided between the connected base portion 45 a and the connected piece portion 45 c. Thus, it is possible to reduce the magnetic flux loop.

The cutting member 200 shown in FIG. 23 is made of metal, for example, and is a rectangular parallelepiped body which has a rectangular or substantially rectangular shape in a cross-section intersecting the axial direction and extends in the axial direction, similarly to the magnet 32. The magnet 32 may be used for the cutting member. In this way, it is possible to reduce the number of members to be used, and it is possible to reduce the number of processes until the rotor 3 is formed. Further, since the magnet 32 and the resin are in contact with each other, the fastening strength can be improved. In the first step of the cutting process for the connecting portion 45 k shown in FIG. 23, the cutting member 200 is disposed axially above the position where a radially outer edge portion of the cutting member 200 coincides with a connection portion between the connecting portion 45 k and the connected piece portion 45 c in the radial direction of the rotor core 40.

Here, the rotor core 40 has a penetrating portion 50. The penetrating portion 50 is configured by the penetrating portion 41 b of the first laminate steel plate 41 and the penetrating portion 42 b of the second laminate steel plate 42 which mutually overlap in the axial direction, and extends in the axial direction.

The penetrating portion 50 has a first penetrating portion 51 and a second penetrating portion 52. The second penetrating portion 52 has a narrower radial width than the first penetrating portion 51. The second penetrating portion 52 has a radial width that can accommodate only the magnet 32. The first penetrating portion 51 has a wider radial width than the second penetrating portion 52. The first penetrating portion 51 has a radial width that can accommodate an outward projection 45 n, which will be described later, in addition to the magnet 32.

The first penetrating portion 51 is formed at an upper portion of the rotor core 40 by a predetermined number of the penetrating portions 41 b of first laminate steel plates 41 and the penetrating portions 42 b of the second laminate steel plates 42 which are laminated adjacent to a lower surface of the connected laminate steel plate 45. The second penetrating portion 52 is formed by the penetrating portions 41 b of the first laminate steel plates 41 and the penetrating portions 42 b of the second laminate steel plates 42 at a position below the first laminate steel plates 41 and the second laminate steel plates 42 which are provided with the first penetrating portion 51.

In the second step of the cutting process of the connecting portion 45 k shown in FIG. 24, the cutting member 200 descends and the connecting portion 45 k is cut. The connecting portion 45 k is cut at a portion connected to the connected piece portion 45 c. The cut connecting portion 45 k becomes the outward projection 45 n of the connected base portion 45 a. The outward projection 45 n extends radially outward from the outer edge portion 45 w of the connected base portion 45 a. The outward projection 45 n is bent toward the first penetrating portion 51 at a root portion of the connected base portion 45 a.

In the third step of the cutting process of the connecting portion 45 k shown in FIG. 25, the cutting member 200 further proceeds to be lowered, and a bent portion of the outward projection 45 n is accommodated inside the first penetrating portion 51. After cutting the connecting portion 45 k with the cutting member 200, the cutting member 200 is removed from the penetrating portion 50.

Next, the manufacturing method of the second modification of the rotor core 40 of the fifth preferred embodiment includes a process of inserting the magnet 32 into the penetrating portion 50. When the magnet 32 is used as the cutting member, the magnet 32 is inserted into the penetrating portion 50 after cutting the connecting portion 45 k.

Also, when the connected laminate steel plate 45 is disposed at the axially lower end of the rotor core 40, the magnet 32 is brought into contact with an upper surface of the connecting portion 45 k, which is the intervened portion of the connected laminate steel plate 45, at the axially lower end in a final step of insertion into the penetrating portion 50.

Next, the manufacturing method of the second modification of the rotor core 40 of the fifth preferred embodiment includes a process of forming the resin portion 34. In this process, the resin portion 34 is formed by pouring a synthetic resin, an adhesive agent or the like into the space portion 33.

In the rotor core 40 of the second modification of the fifth preferred embodiment, the connected laminate steel plate 45 disposed at the axially upper end has the outward projection 45 n which extends radially outward from the outer edge portion 45 w of the connected base portion 45 a. According to this configuration, a flux barrier such as an air layer or a resin layer 34 can be provided between the connected base portion 45 a and the connected piece portion 45 c of the connected laminate steel plate 45. This makes it possible to more effectively utilize the magnetic flux of the magnet 32. Further, before forming the outward projection 45 n, that is, before cutting the connecting portion 45 k, it is possible to prevent the first base portion 41 a and the piece portion 41 c from being separated from each other and the second base portion 42 a and the annular portion 42 c from being separated.

In addition, instead of the outward projection 45 n, the rotor core 40 may be provided with an inward projection extending radially inward from the inner edge portion of the connected piece portion 45 c. Further, the rotor core 40 may be provided with both of the outward projection 45 n and the inward projection.

Since the outward projection 45 n is bent toward the penetrating portion 50, it presses the magnet 32 outward in the radial direction with its elastic force. Thus, the positioning of the magnet 32 can be performed in the radial direction. Further, it is possible to enhance the function of fixing the magnet 32 to the rotor core 40. In addition, the inward projection in the first modification and the outward projection 45 n in the second modification may be combined. In this case, since the outward projection 45 n is pressed radially outward, it can be caught by the inward projection and thus prevented from falling off.

Since a bent portion of the outward projection 45 n is accommodated inside the first penetrating portion 51, it does not interfere with the insertion of the magnet 32 into the penetrating portion 50. Therefore, it is possible to secure a space for inserting the magnet 32 in the penetrating portion 50.

Also, the manufacturing method according to the second modification of the rotor core 40 of the fifth preferred embodiment may include a process of forming the thickness of the connecting portion 45 k in the axial direction to be thinner than those of the connected base portion 45 a and the connected piece portion 45 c before the process of cutting the connecting portion 45 k with the cutting member 200. According to this configuration, it is possible to easily cut the connecting portion 45 k. For example, press working may be performed. According to this configuration, it is possible to obtain a configuration capable of easily cutting the connecting portion 45 k by a simple processing method.

Also, the manufacturing method according to the second modification of the rotor core 40 of the fifth preferred embodiment may include a process of providing a notch in the connecting portion 45 k before the process of cutting the connecting portion 45 k with the cutting member 200. According to this configuration, it is possible to easily cut the connecting portion 45 k. For example, push back processing may be performed. According to this configuration, it is possible to obtain a configuration capable of easily cutting the connecting portion 45 k by a simple processing method.

Next, a motor according to a sixth preferred embodiment of the present invention will be described. FIG. 26 is a perspective view of a rotor core of the motor according to the sixth preferred embodiment of the present invention as viewed from above. FIG. 27 is a perspective view of the rotor core of the motor according to the sixth preferred embodiment of the present invention as viewed from below. FIG. 28 is a plan view of a first laminate steel plate of the rotor core according to the sixth preferred embodiment of the present invention. FIG. 29 is a plan view of a second laminate steel plate of the rotor core according to the sixth preferred embodiment of the present invention. Since a basic configuration of this preferred embodiment is the same as that of the first preferred embodiment described above, constituent elements common to those in the first preferred embodiment are denoted by the same reference numerals or the same names as before, and explanation thereof may be omitted.

The rotor core 40 shown in FIGS. 26 and 27 has first laminate steel plates 46 and second laminate steel plates 47. Each of the first laminate steel plates 46 and the second laminate steel plates 47 expands in the radial direction with respect to the central axis of the rotor core 40.

The first laminate steel plate 46 shown in FIG. 28 has a first base portion 46 a, penetrating portions 46 b, and piece portions 46 c. The first base portion 46 a has a hole portion 46 d and recessed portions 46 e.

The second laminate steel plate 47 shown in FIG. 29 has a second base portion 47 a, penetrating portions 47 b, and annular portions 47 c. The second base portion 47 a has a hole portion 47 d and recessed portions 47 e. The annular portion 47 c has a large diameter portion 47 f and small diameter portions 47 g which have different outer diameters.

The rotor core 40 shown in FIG. 26 and FIG. 27 is formed by laminating a plurality of first laminate steel plates 46 having the above-described structure and at least one second laminate steel plate 47 having the above structure in the axial direction. At this time, the piece portion 46 c of the first laminate steel plate 46 and the large diameter portion 47 f of the annular portion 47 c of the second laminate steel plate 47 overlap in the axial direction, and the first laminate steel plate 46 and the second laminate steel plate 47 are laminated at a position where their outer peripheral edges are partially aligned.

According to this configuration, there is no region of a steel plate over the entire region in the circumferential direction between the first base portion 46 a and the piece portions 46 c of the first laminate steel plate 46 and between the second base portion 47 a and the annular portions 47 c of the second laminate steel plate 47. As a result, a flux barrier such as an air layer can be provided between the first base portion 46 a and the piece portion 46 c and between the second base portion 47 a and the annular portion 47 c. Therefore, it is possible to more effectively utilize the magnetic flux of the magnet 32.

Since the number of the second laminate steel plates 47 is smaller than the number of the first laminate steel plates 46, it is possible to suppress the amount of magnetic flux flowing through the annular portions 47 c of the entire rotor core 40 as compared with the case where all of the rotor core 40 is formed by the second laminate steel plates 47. Therefore, the occurrence of magnetic saturation in the annular portion 47 c is suppressed, so that the magnetic flux of the magnet 32 can be more effectively utilized.

When a synthetic resin, an adhesive or the like is poured on radially outer sides of the first base portion 46 a and the second base portion 47 a after inserting the magnet 32 into the penetrating portions 46 b and 47 b, the synthetic resin, adhesive or the like intrudes into the recessed portions 46 e and 47 e. Thus, it is possible to firmly fix the piece portion 46 c, the annular portion 47 c, and the magnet 32.

Next, a motor according to an exemplary seventh preferred embodiment of the present invention will be described. FIG. 30 is a perspective view of a rotor of the motor according to the seventh preferred embodiment of the present invention as seen from above. FIG. 31 is a plan view of the rotor of the motor according to the seventh preferred embodiment of the present invention. Also, since a basic configuration of this preferred embodiment is the same as that of the first preferred embodiment described above, constituent elements common to the first preferred embodiment are denoted by the same reference numerals or same names as before, and explanation thereof may be omitted.

The rotor 3 shown in FIGS. 30 and 31 has a cylindrical or substantially cylindrical shape extending in the axial direction. The rotor 3 is disposed with a predetermined gap provided radially inside a stator 2 (see FIG. 1). The rotor 3 has a shaft 31 (not shown), a rotor core 40, magnets 32, and space portions 33 or resin portions 34.

The resin portion 34 is provided by injecting a synthetic resin, an adhesive agent or the like into the space portion 33. As a result, the resin portion 34 plays a role as a flux barrier. Further, since both circumferential ends of the magnet 32 contact the resin portions 34, it is possible to firmly fix the magnet 32 to the rotor core 40.

The rotor core 40 has first laminate steel plates 46. The first laminate steel plate 46 has a first base portion 46 a, penetrating portions 46 b, and piece portions 46 c. The first base portion 46 a has a hole portion 46 d and recessed 46 e.

The penetrating portion 46 b is formed as a gap between the first base portion 46 a and the piece portion 46 c. The magnets 32 are provided one by one for each of eight penetrating portions 46 b. Eight column portions 33 a are disposed between adjacent penetrating portions 46 b (magnets 32) in the circumferential direction and pass through the rotor core 40 in the axial direction.

A circumferential length L1 of the piece portion 46 c shown in FIG. 31 is shorter than a circumferential length L2 of the magnet 32. According to this configuration, the magnetic characteristics related to a cogging torque can be improved. Therefore, it is possible to reduce the cogging torque. Furthermore, it is possible to suppress the generation of the magnetic flux loop inside the rotor core 40.

The recessed portion 46 e is provided in an angular region with respect to the central axis between the piece portions 46 c adjacent to each other in the circumferential direction. The recessed portion 46 e is recessed radially inward from an outer edge portion 46 w of the first base portion 46 a. According to this configuration, when a synthetic resin, an adhesive or the like is poured on a radially outer side of the first base portion 46 a after the magnet 32 is inserted between the first base portion 46 a and the piece portion 46 c, that is, the penetrating portion 46 b, the synthetic resin, adhesive or the like intrudes into the recessed portion 46 e. Thus, it is possible to firmly fix the piece portion 46 c and the magnet 32.

Although the preferred embodiments of the present invention have been described above, the scope of the present invention is not limited thereto, and various modifications can be made without departing from the spirit of the invention. Further, the above preferred embodiments and modifications thereof can be arbitrarily combined as appropriate.

For example, although the annular portions 42 c and 47 c and the connected annular portion 43 c described in the above embodiments are annularly connected over the entire circumference, a part of them in the circumferential direction may be in a locally discontinued shape.

Further, in the second, third and fourth embodiments, the connected laminate steel plate is arranged only at the lower end in the axial direction, the connected laminate steel plates may be disposed at both of the lower end and the upper end in the axial direction. In the case where the connected laminate steel plates are disposed at both of the lower end and the upper end in the axial direction, the connected laminate steel plates having different shapes may be disposed at the lower end and the upper end in the axial direction.

In addition, as the stator according to the embodiment of the present invention, a stator such as a claw pole type is also applicable.

The present invention can be used, for example, in rotor cores, rotors, and motors.

Features of the above-described preferred embodiments and the modifications thereof may be combined appropriately as long as no conflict arises.

While preferred embodiments of the present invention have been described above, it is to be understood that variations and modifications will be apparent to those skilled in the art without departing from the scope and spirit of the present invention. The scope of the present invention, therefore, is to be determined solely by the following claims.

-   -   1-17. (canceled) 

18. A rotor core comprising: a plurality of laminate steel plates each extending in a radial direction with respect to a central axis; each of the laminate steel plates including: a base portion positioned on a radially outer side of the central axis; and a plurality of pieces separately disposed on a radially outer side of the base portion with penetrating portions therebetween, and arranged side by side at predetermined intervals in a circumferential direction; wherein the plurality of laminate steel plates are laminated in an axial direction; the laminated steel plate disposed at an upper end in the axial direction includes at least one of an outward projection extending radially outward from an outer edge portion of the base portion and an inward projection extending radially inward from an inner edge portion of the piece; and the laminated steel plate disposed at a lower end in the axial direction includes an intervening portion that intervenes between the base portion and the piece.
 19. The rotor core according to claim 18, wherein the intervening portion is a connecting portion which connects the base portion and the piece.
 20. The rotor core according to claim 18, wherein the outward projection or the inward projection bends toward the penetrating portion.
 21. The rotor core according to claim 20, wherein the penetrating portion includes a first penetrating portion and a second penetrating portion with a narrower radial width than the first penetrating portion; and a bent portion of the outward projection or the inward projection is accommodated inside the first penetrating portion.
 22. The rotor core according to claim 18, wherein, in an angular region with respect to the central axis between the pieces adjacent to each other in the circumferential direction, the base portion includes protruding portions protruding radially outward from an outer edge portion thereof.
 23. The rotor core according to claim 18, wherein, in an angular region with respect to the central axis between the pieces adjacent to each other in the circumferential direction, the base portion includes recessed portions recessed radially inward from an outer edge portion thereof.
 24. A rotor comprising: the rotor core according to claim 18; and a plurality of magnets disposed in the penetrating portions of the rotor core; wherein the rotor core includes a plurality of space portions which are disposed between the penetrating portions adjacent to each other in the circumferential direction, and penetrate the rotor core in the axial direction.
 25. The rotor according to claim 24, further comprising a resin portion provided in the space portion.
 26. A motor comprising the rotor according to claim
 24. 27. A manufacturing method of a rotor core in which a plurality of laminate steel plates extending in a radial direction with respect to a central axis are laminated in an axial direction, the method comprising: laminating divided laminate steel plates in the axial direction, each of the divided laminate steel plates including a base portion positioned on a radially outer side of the central axis, and a plurality of pieces separately disposed on a radially outer side of the base portion with penetrating portions therebetween, and arranged side by side at predetermined intervals in a circumferential direction; laminating a connected laminate steel plate including the base portion and the pieces connected via connecting portions at an upper end in the axial direction of the divided laminate steel plates that are laminated; laminating an intervening laminate steel plate including intervening portions that intervene between the base portion and the pieces at a lower end in the axial direction of the divided laminate steel plates that are laminated; and cutting the connecting portions with a cutter by inserting the cutter into the penetrating portions.
 28. The manufacturing method of the rotor core according to claim 27, further comprising making a thickness of the connecting portion in the axial direction thinner than each of the base portion and the piece portion.
 29. The manufacturing method of the rotor core according to claim 27, further comprising providing a notch in the connecting portion.
 30. The manufacturing method of the rotor core according to claim 28, wherein, in the making the thickness of the connecting portion in the axial direction thinner than each of the base portion and the piece or the process of providing the notch in the connecting portion, press working is performed.
 31. The manufacturing method of the rotor core according to claim 28, wherein, in the making the thickness of the connecting portion in the axial direction thinner than each of the base portion and the piece or the process of providing the notch in the connecting portion, push back processing is performed.
 32. A manufacturing method of a rotor using the rotor core manufactured by the manufacturing method of the rotor core according to claim 27, wherein a magnet is used as the cutter.
 33. A manufacturing method of a rotor using the rotor core manufactured by the manufacturing method of the rotor core according to claim 27, comprising a process of cutting the connecting portion with the cutter, and then removing the cutter from the penetrating portion and inserting a magnet into the penetrating portion.
 34. The manufacturing method of the rotor according to claim 32, wherein the magnet is brought into contact with the intervening portion in a final step of insertion into the penetrating portion. 